1. Field of the Invention
The present invention relates to a portable terminal. More particularly, the present invention relates to an apparatus and a method for antenna matching of a portable terminal.
2. Description of the Related Art
A transceiver apparatus for wireless communication includes an antenna and a transmission circuit in order to transmit and receive a wireless signal. However, mismatching between the antenna and the transmission circuit degrades performance of the transceiver apparatus. To address this antenna mismatching, a conventional method adopts a Fixed Matching Network (FMN) scheme using a fixed Inductor-Capacitor (LC) circuit. However, this method takes a considerable time to find an optimal matching value. Moreover, since it is impossible to change the LC circuit value according to the electric field in which the transceiver is operating, a Radio Frequency (RF) performance problem, in particular a problem such as a dropped call and a high talk current, frequently occurs when the transceiver operates in a weak electric field.
One technique devised to compensate for the drawbacks of the FMN scheme is a Tunable Matching Network (TMN) scheme. The TMN scheme accomplishes the antenna matching with the optimal value based on the electric field and the user environment using variable elements, rather than the fixed LC circuit. Thus, the RF performance is enhanced in various electric field situations without changing the antenna.
However, when the TMN scheme is applied, full consideration is not given to factors affecting the antenna radiation performance according to the manner and environment in which a portable terminal is actually used. Such consideration is necessary because the antenna radiation performance is greatly affected by the body effect and the environmental interface such as the position of the portable terminal. Hence, to optimize the antenna matching, it is necessary to consider various environmental characteristics. For example, the position or the direction in which the portable terminal is held exerts influence on the antenna performance. In this regard, there is a need for an improved method for tuning a TMN circuit.